Air cleaner



Dec. 13, 1966 Filed Aug. 28, 1964 l. UPOR AIR CLEANER 5 Sheets-Sheet l TTS: l-

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AIR CLEANER Filed Aug. 28, 1964 5 Sheets-Sheet 5 f1-Er. E-

INVENTOR.

/STVAN UPU/ Aflorneys United States Patent O I 3,290,868 AIR CLEANER Istvan Upor, Pittsburgh, Pa., assigner, by mesne assignments, to Air Kleener Corporation of America, Pittsburgh, Pa., a corporation of Pennsylvania Filed Aug. 28, 1964, Ser. No. 392,790 4 Claims. (Cl. 55-543) This invention is for an apparatus for removing dust, pollen and other suspended solids from air, and constitutes an improvement on an apparatus for this purpose disclosed in Patent No. 2,839,153 granted June 17, 1958 to William I. Mollner.

Apparatus of the type to which this invention relates, and as disclosed in the Mollner patent above referred to, comprises a succession of passages through which the air is moved in which the air flows from one passage to the next through a curved duct. In each passage the air flow is divided into two streams, the main stream having a series of brushes or similar devices providing a curtain of bristles through which the air flows, and a second passage, which is a lesser one, positioned below the first in a location most advantageous for receiving that part of the stream carrying the more massive dust particles. It is arranged to trap and retain the particles while the air continues to ilow through it and return into the main stream after the main stream has passed through the brushes. This second passage, according to the present invention, may also have one or more brushes therein.

The brushes may have iine wire bristles, but certain plastic bristles, as for example those made of polystyrene,

are more satisfactory, but in any case they are relatively long as contrasted to short, stiff bristles, so that they may flex and vibrate in the air stream, but they are not so long and soft as to blow over and lay flat when air is blowing `through them. It is presently postulated that the air, striking the pervious curtain of bristles, sets up a condition of turbulence, and at the same time the individual bristles flex and `sway through the air, and this action produces static electrical charges that cause dust and minute air-brone particles to agglomerate. In flowing in a curved path to the next passage, the inertia or centrifugal force carries the aggregations so formed to the outside of the curve into the stratum of air that will be diverted into the trap of the secondary stream of the succeeding passage.

The present invention is for an improved construction designed to provide a more ecient cleaning of the air and provide improved arrangements for separating the air into two streams. It is also designed to provide more convenient access for periodic cleaning and to substantially reduce the cost of manufacture over the devices originally provided, and as shown in said patent. The invention also provides an arrangement wherein the velocity of the air is increased afte"`r moving through each pass to more effectively separate the dust, but with less pressure drop than in the previous constructions of this type.

These and other objects and advantages are secured by this invention as will be more fully understood by reference to the accompanying drawings, in which:

FIG. 1 is a vertical section through an air cleaner embodying this invention wherein the unit is designed to be coupled into a duct system with an external fan, not shown;

FIG. 2 is a perspective view of the cabinet with the cleaner elements removed;

FIG. 3 is a view similar to FIG. l of a modification wherein there is a fan in the unit, this unit being designed as a room air cleaner which is entirely self-contained; and

FIG. 4 is a fragmentary view in transverse vertical section and on a larger scale showing in clearer detail 3,290,868 Patented Dec. 13, 1966 the manner in which the trap units and their brushes are slidably supported for insertion into and removal from the casing.

Referring rst to FIG. 1, the device here shown cornprises a cabinet having a frame comprised of four corner posts S, upper horizontal connecting members 6, and lower horizontal frame members. It has three full side walls 7, a closed top 8, and a bottom 9. The fourth side has a hinged door 10 covered With a foamed plastic panel sealing strip 10a which seals against the parts inside the cabinet. The side wall 7 which is opposite the door has a similar panel on its inner face.

As here illustrated, one side wall which is at right angles to the side with the door, has an air inlet connection 11 near the top that opens to the interior of the cabinet, and a similar extension or connection 12 that is near the bottom. The upper extension may be connected, for example, into the return air duct of a hot air heating system, and the connection 12 coupled into air intake blower of such a furnace so that when the furnace blower is circulating air, such air flows through the unit to the furnace. However, the device may be coupled into any air duct system having means for effecting positive air circulation through the unit, or as will hereafter be described, it may be simply a standing unit with no ducts and a self-contained air-circulating fan.

Within the casing is the air cleaner. This comprises a top pass 15 defined between an upper plate 16 and a lower plate 17. One side wall of this pass is formed by the casing side wall 7 opposite the door, and the door, when closed, provides the other side wall. Air to be cleaned ilows through this pass in the direction of the arrows in FIG. l.

At the inner end of the top plate there is a substantially semi-circularly curved sheet 19 that joins the top of the first pass and joins to the lower plate 20 of a second pass 21 while an extension 17a, here shown as a separate piece, at the inner end of plate 17 also forms the upper wall of this second pass. In the first pass 15 is a divider plate 22rthat is spaced above the lower plate, and which is closer to the lower plate than to the upper plate 16. The air entering the top passage 15 is separated by the divider plate into two streams, one flowing over and one under the divider. The divider plate is here shown as the top of a box-like duct or shell having an open entering end, a bottom, above referred to as 17a, that forms in effect an extension of the bottom plate 17. This bottom is turned upwardly at its down-wind end to form a bafile 18 that extends only partway up to the divider plate 22. The inner end of the divided plate extends over the top edge of the bafiie 18 in spaced relation thereto and then extends around in a semi-circle 23 to discharge that part of the air stream which passes under the divider and over the baffle 18 into the entering end of the second pass at 24.

The semi-circular inner plate 23 and the curved outer plate or sheet 19 are eccentric in that the center of curvature for the plate 23 is located between the sheet 19 and its center of curvature. As a result of this the main passage above the divider plate decreases gradually from a maximum dimension A at the beginning of the curve to a minimum dimension B about halfway around where 23 and 29 are in closest confronting relation and then expands again to the full distance C between the under surface of the extension 17a of plate 17 at the top and plate 20 at the bottom of the second pass. The first pass thus communicates with the second one through a venturi-like passage that tapers from the entering point to a throat of minimum section and then lgradually enlarges, this passage extending through about from the discharge of the first unit to the entrance of the second.

In flowing from the first passage to the second, the

direction of air flow is reversed and the air which comprised the top part of the stream in the first pass, to the extent that it remains stratified, becomes the lower portion of the stream entering the second pass.

The second pass and all succeeding intermediate passes are essentially the same in that at the discharge end of each horizontal pass there is a curved deiiector plate 25 similar to the sheet or plate 19 for inverting the air stream and reversing its flow. In each there is a divider plate 26 similar to plate 22 of the first path with a curved extension 27 similar to 23 of the first pass. The lowermost pass 28 opens straight outward through outlet 12, and in this one the divided plate is, as in the other passes, the top 29 of a box-like structure having a bottom 30, an end wall at the discharge end which extends from the bottom to the top, providing a dead end pocket. In all the passes, as in the first, one side wall of the cabinet closes the side wall of the passes, and the door the other.

In the larger or upper division of the air passage in the several passes above the divider plate is a plurality or set of several horizontally-extending long-bristle brushes 35, the bristles of one brush preferably reach only to, or even stopping short of the peripheral area of the next brush so that the ends of the bristles do not overlap and leave a slight open gap between the brushes. The brushes may have a usual core 36 and the bristles 37 may be thin wire, but preferably they are of .a plastic composition, such as polystyrene, which is practically 100% non-absorbent to moisture and therefore is not affected by humidity, and which will flex and not become brittle over an indefinite period of time. There are two more such brushes 38 in tandem in the lesser air passage under the divider plate between the entrance and the baffle, one being behind the other, and one desirably being higher than the other.

The brushes of the larger upper stream are supported ou upright spacing bars 39 at each end, and the brushes in the lesser passage are supported on horizontally-extending -bars 40 secured to .the sides of the box-like duct in which the brushes are located.

In the construction shown, all of that assembly which comprises the divider plates and the brushes with their supports may be slid sideways and removed as separate units from inside `the cabinet when the door is opened. The tops of the brush supports 39 are connected by a cross strip 41 which is bent to channel form. In the top of the cabinet there is a fixed guide strip 43 that fits into the channel in cross piece 41 of the first pass to provide a sliding t. The bottom of the duct forming the divider has a similar guide 44 formed therein. It in turn has a sliding fit in a fixed cross strip 43 similar to the one above. It is supported in the cabinet frame between the plate 17 and the top edge of 25. Below this is a cross strip A41, joining the side supports 39, the same as 41 above, with a channel 42 that slidably engages the guide strip 43. This arrangement is repeated for each stage, with the guide strip 43 for the lowermost stage being supported in the bottom. Each unit comprising the trap and its brushes and the brushes above may be completely removed.

In operation the Iheavier particles of dirt or solids in the air will by the action of gravity be for the most part in the lower portion of the entering air stream. This part of the stream will pass under 'the divider plate of the first pass. The air passing against and between the bristles of the brushes and then against the vertical bafiies, deposits the most of these heavier solids in front of the baille. To some extent the brushes in this lesser stream passing under the divider may be compared to `a familiar vertically-slotted snow fence that offers low wind resistance, but effects precipitation of the snow on the downwind side. The dust that may tend to cling to the bristles is dislodged by their constant flexing in the current of air, so that while dust collects forwardly of the vertical baffle, it does not collect in substantial quantities in the brushes as it would in a filtering screen across this passage. Consequently the pressure drop or resistance to air iiow never builds up in the passage but remains constant. Particles that may not have been captured in this pass are carried with the air under curved baflie 23 into the next pass.

The larger air stream, passing over the divider, encounters the curtain of bristles in the brushes 35. Some of the dust particles and solids may pass through the bristles, but their velocity will be checked. Smaller particles may adhere to the bristles or be attracted by static charges induced by the liow of air through the bristle. As thus arrested, they are `contacted by or attracted to other particles, appearing to accumulate into clusters that then leave the area of the bristles into the downwind side of the bristles. Here the velocity of the stream of air increases toward the narrowing of the passage at dimension B and the particles tend to move into the stream nearest the outer curved plate 19 and are carried around into the next trap under the divider plate in the second pass. This operation repeats in each pass and usually four passes as shown will result in the removal of a large percentage of the solids, even including particles which individually are not optically discernible, such as tobacco smoke and pollen.

That there is induced a natural electrical phenomenon in the operation of the unit is indicated by the fact that the negative ion count of the emerging air is higher than in the entering air, and this is desirable from the standpoint of reducing odors and beneficially conditioning the air for breathing.

Since the 4brush-containing passages under the divider plates comprise traps in which dust and solids collect, it is desirable to slide the units out as above described from time to time, depending on the atmosphere being cleaned, to remove collected dust. This may be done, for example, by tilting the unit when it is removed so that the entering end of the trap is lowerfmost and tapping it lightly against a paper spread over the iioor or other Isurface or by vacuum cleaning the tray. The operation of the unit is improved over that disclosed in the prior patent above referred to, first because of the air passages, reducing from a large area at A to a smaller area at B, and then expanding at C and also by the use of traps that open endwise under the divider plates directly into line with the entering flow, avoiding louvres or like structures and through the use of brushes in the trap portions forwardly of the vertical baffles.

In the construction shown in FIG. 3 the same general construction is employed and corresponding reference nu merals designate corresponding parts. In this figure, however, the unit is a free standing unit that draws air in through the top of the cabinet and discharges it at the bottom. To this end, the cabinet has a grill over the top and for a few inches down the sides for the intake of air, the grill being designated 50. There is a vertical opening 51 through the top sheet 16 and the bottom plate sheet for forming the bottom of the first pass is designated 52. It is curved toward the dust trap and divider. Beyond this point all of the parts and arrangements are the same as in FIGS. l to 3 inclusive. Instead of the last or bottom pass opening through the side of the cabinet, as in FIG. l, the bottom sheet 53 has an opening 54 into an exhaust chamber 55, and a curved plate 56 directs air flow downwardly in this opening. A central opening in the bottom 57 of this chamber discharges air into the center of a centrifugal blower 58, driven by a motor 59. Air discharged from the periphery of the blower escapes laterally in all directions through grill panels 60 at the sides of the bottom of the cabinet. This air has a low velocity in any direction so as to minimize noticeable draft over the floor in any direction.

In both constructions there is a cabinet having a ver- .tical stack of similar but alternately reversed units there- 1n, defining with the sides of the cabinet a sinusoidal air passage with the passage in each sinuous curve of the diminishing and then enlarging area, and with an open ended trap in the bottom of each pass between curves.

With this construction it is particularly desirable to sterilize and deoderize the air. For this purpose an ultraviolet tubular lamp or known construction is mounted at 61 on the last curved sheet 19 below the curved sheet 23. In this position its rays are directed upwardly into the path of the approaching air and diagonally toward the plate or sheet 56 so that the air is exposed to its radiation through a considerable distance in its nal travel through the unit. It is desirable to provide a second such lamp 61a on the curved sheet 56 so that it radiates the air approaching this sheet and also radiates through opening 54 into the discharge chamber. These lamps ionize the air and generate Within permissible limits ozone and thereby effectively destroy odors, adapting them for use in hospitals as well as taverns and eating establishments where the air is to be cleaned but from which it is desirable also to remove odors.

While I have shown and described in detail certain embodiments of my invention, it will be understood that various changes in the construction and arrangements of parts within the contemplation of my invention and under the scope of the following Claims.

I claim:

1. An air cleaner of the class described comprising a succession of stacked similar but alternately-reversed units through which the air to be cleaned flows in series, each unit having a horizontal passageway with an entering end and discharge end and with a horizontal divider plate therein set inwardly from its entering end positioned to ydivide the air flow into a lesser lower stream and a larger upper stream, means in the passage for the upper stream above the divider plate providing a curtain of exible bristles through which the upper stream of air must dow, a dust-obstructing battle below the divider plate extending crosswise of the lower stream and providing a passageway over the bafe and under the divider plate through which the lesser stream of air passes, means providing transverse rows of bristles under the divider plate in advance of the baille through which the lower stream of air flows, a curved sheet extending from the top of the upper unit at the discharge end of the passageway to the bottom of the entrance end of the unit next below, and

a `curved sheet extending from the horizontal divider plate at the discharge end of the passageway of the upper unit and directing it into the top of the entering end of the passageway of the unit next below.

2. An air cleaner as dened in claim 1 wherein the lastnamed curved sheet extends toward the rst curved sheet for restricting the passageway between said sheets to an a-rea smaller than the area of the passageway through the unit whereby the Velocity of the air passing from the discharge end of one unit into the entering end of the passage of the next is increased.

3. An air cleaner as dened in claim 1 wherein the horizontal divider in each passageway and said curved sheet for directing the lesser stream of air from the unit above into the top of the entering end of the passageway of the unit next below together with the means in the upper passage providing a curtain of flexible bristles are integrated, the structure providing guideways in which each of said integrated assembly is slidably positioned for removal sideways from the passageway across which it extends, and an enclosure around said stack of units having a door through which each said integrated assembly rnay be removed.

4. An air cleaner as defined in claim 1 wherein the unit at the bottom of the stack has the discharge end of its passageway opening downward, means forming a chamber below the stack into which the air .passes downwardly from the opening in the lowermost unit and, a motordriven fan below said chamber arranged to withdraw air from the chamber and discharge it at the base of the stack.

References Cited by the Examiner UNITED STATES PATENTS 718,805 1/1902 Watts 55--485 X 1,521,576 12/1924 Wittemeier 55-484 X 1,630,748 5/ 1927 Kirkpatrick 55-342 X 2,197,004 4/ 1940 Myers 55-484 X 2,804,937 9/1957 Poole 55-103 2,839,153 6/ 1958 Mollner 55--224 2,873,000 2/1959 Elam 55-138 2,945,554 7/1960 Berly 55-279 ROBERT F. BURNETT, Primary Examiner. 

1. AN AIR CLEANER OF THE CLASS DESCRIBED COMPRISING A SUCCESSION OF STACKED SIMILAR BUT ALTERNATELY-REVERSED UNITS THROUGH WHICH THE AIR TO BE CLEANED FLOWS IN SERIES, EACH UNIT HAVING A HORIZONTAL PASSAGEWAY WITH AN ENTERING END AND DISCHARGE END AND WITH A HORIZONTAL DIVIDER PLATE THEREIN SET INWARDLY FROM ITS ENTERING END POSITIONED TO DIVIDE THE AIR FLOW INTO A LESSER LOWER STREAM AND A LARGER UPPER STREAM, MEANS IN THE PASSAGE FOR THE UPPER STREAM ABOVE THE DIVIDER WHICH THE UPPER STREAM OF AIR MUST FLOW, BRISTLES THROUGH WHICH THE UPPER STREAM OF AIR MUST FLOW, A DUST-OBSTRUCTING BAFFLE BELOW THE DIVIDER PLATE EXTENDING CROSSWISE OF THE LOWER STREAM AND PROVIDING A PASSAGEWAY OVER THE BAFFLE AND UNDER THE DIVIDER PLATE THROUGH WHICH THE LESSER STREAM OF AIR PASSES, MEANS PROVIDING TRANSVERSE ROWS OF BRISTLES UNDER THE DIVIDER PLATE IN ADVANCE OF THE BAFFLE THROUGH WHICH THE LOWER STREAM OF AIR FLOWS, A CURVED SHEET EXTENDING FROM THE TOP OF THE UPPER UNIT AT THE DISCHARGE END OF THE PASSAGEWAY TO THE BOTTOM OF THE ENTRANCE END OF THE UNIT NEXT BELOW, AND 